Your main character is stuck on a small island with only three items. You get to decide what three items. They could be deeply practical items like a water filter and a lighter or they can be purely random, unpractical items like lipstick and hairspray.
The main character must be alone. There are no other people on the island. There can be animals though.
How your character ended up on this island is up to you. Your character doesn’t have to be shipwrecked, he could have been on a plane that crashed or she could be a survivalist who was deliberately stranded on the island for a period of time.
You also get to decide what your characters focus will be. Will he or she be determined to survive or to escape, or is there a third option? Maybe they will use all that free time to write poems. Their fate is up to you.
Don’t spend too long planning this writing, just picture a main character and an island in your head and start writing, see where the words lead you.
Happy writing!